Expression of p53 and p16 in actinic keratosis, bowenoid actinic keratosis and Bowen's disease.

INTRODUCTION: Bowen's disease (BD) and bowenoid actinic keratosis (bAK) have traditionally been differentiated according to the presence or absence of dysplasia in the follicular epithelium. p16 has been suggested to be a useful tool to make the differential diagnosis between BD and AK and as a marker of bad prognosis. MATERIALS: Five biopsies of BD, five of AK and five of bAK where stained for p53 and p16.
RESULTS: All lesions showed positive immunostaining of p53, affecting to the lower two thirds of the epidermis in BD and bAK, and only the basal layer in non-bAK. All the BD and bAK cases were positive for p16, showing a similar immunostaining pattern, whereas no staining was observed in non-bAK. DISCUSSION AND
CONCLUSION: These findings suggest a common pathogenic mechanism for BD and bAK. bAK might have worse prognosis than AK. p16 might not be useful as a tool for differential diagnosis between AK and BD because bAK and BD show an extremely similar immunohistochemical pattern.